Hermes Birkin

 
 
A A are carried in fixed bearings at each end in the frame of the machine; while the third roller B slides vertically in the frame, and is lowered by the screws C C at each time of passing the plate through the rollHermes bagss, to give the required degree of curvature to the plate. The screws 0 C were at first worked by hand, but are now driven by gearing from the main shaft. As the thickness of the body of the plate is only A in., while the thickness of the edges is { in., a liner-plate, .fg in. thick, is laid over the body of the boiler-plate iHermes Birkin n the bending process, in order to make up the same thickness of $ in. throughout for passing through the rolls; and the liner-plate is afterwards flattened again ready for subsequent use. At one end of each of the lower rollers A A is a groove D to receive the flange of the plate; this groove is shown enlarged in Fig. 2165, and is formed by a glut-piece or ring E, screwed upon the roller-spindle F and tightened by aBirkin set screw G, by means of which the width of the groove can be increased or diminished according to the thickness of Hermes outletthe flange of the plate. A corresponding groove is provided at the opposite end of the upper roller B, to allow of bending plates with the flange inside instead of outside. In order to obtain a sufficient hold upon the plate to pass it through the rolls, the surfaces of all the rollers are fluted longitudinally with shallow flutes at 1J in. pitch, as sHermes Kellyhown in Fig. 2165, and enlarged to half full size
in the section, Fig. 2166. The lower rollers only are driven by gearing• the upper roller being merely a pressing roller for giving the required curvature to the plates, and weighing about 25 cwt. The working speed of the rollers is three revolutions a minute, or about 12 ft. a minute speed of surface.
The two semicircular plates are then welded together into a single ring, to form one length of the boiler barrel. The edges to be welded are first heated in the fire at A, Fig. 2167, and upset sufficiently to give the required thickness of metal for forming the scarf weld. A welding heat is then taken on a short length of the joint of the pHermeslates, and the plates B are welded together along the joint upon the welding anvil, shown in Figs. 2167, 2168. The anvil-face C is shaped to the internal diameter of the boiler barrel, and is separate from the pedestal D of the anvil, so that it can he exchanged for other sizes of face, according to the diameter of the boiler. During the heating and welding, the plates B are held in the circular frame E, in which they are securely clamped; and the frame E being slung from a crane, the plates are readily handled. The two ends of the joint Hermes Handbagsare first tacked together by welding, to secure the correct diameter of barrel, and the joint is then welded in short lengths from the centre towards each end.